Hi @veepatel
Confirm the input voltage on your Keurig K55
there should be a label mentioning about input voltage, e.g. 110V
In UK, voltage is supplied at 230V....
If your device is labelled at 110V and you connect it to 230V, likely is could be damaged.
I think you mean step down voltage transformer (drop voltage from 230V to 110V), you need to consider on your coffee maker power consumption also. Not all converter might be suitable of this.
update us first on your current machine voltage input.